An increasing amount of effort has been deployed to increase the switching and processing capabilities of systems used in telecommunications and computing frames. The optical solution has been shown to be an efficient way forward.
Challenges arise in adapting electrical-based systems for optical compatibility. In electrical switching systems and servers, for example, the backplane of a chassis enclosing electronic circuit cards (also referred to herein as line cards, blades, nodes or switch cards) permits the routing of electrical signals from one card to another. A ‘switch card’ is typically used to direct the signals between line cards. Electrical interconnects between blades can however be very power consuming, require signal compensation techniques, and tend to suffer from large amounts of electro-magnetic interference and emission, which further limits the system's performance. The optical line card was thus introduced to address such limitations.
With the optical line cards, the ‘optical’ backplane replaced the all-electrical backplanes of older line card chassis. As the term indicates, “back-plane”, the backplane is a backend of the chassis. Each line card is inserted inside the chassis, towards the backplane. Typically, optical line cards have an optical connector at their respective back ends to connect with the optical layer of the ‘optical’ backplane. Once conversion from optical high-speed multi-wavelength signals to electrical signals is achieved in the cards, the electrical signals can be routed back into the electrical portion of the ‘optical’ backplane, and in turn, enable the switching of microchips of other line cards for example. The term ‘optical’ backplane thus refers to a hybrid backplane with both electrical and optical connections within its layers.
A number of shortcomings such as optical coupling issues arise with prior art backplane chassis. Since the cards and the backplane are perpendicular to one another, typical interconnects involve the use of right-angle turn connectors, which are non ideal especially with regards to optical coupling efficiency. Prior art interconnecting are also limited in that complex alignment strategies are often required. In addition, periodical cleaning of the optical interfaces between the connectors is quite a challenge since interconnects reside deep inside the chassis, near the back end.
There is thus a need for an improved backplane chassis which addresses at least some of the issues associated with the prior art.